lock ACURA NSX 1991 Service Repair Manual

Engine Removal/Installatio n
Removal
32. Remov e th e lef t an d righ t parkin g brak e cable s (se e
sectio n 19 ).
33 . Remov e th e rea r bea m ro d assembl y an d parkin g
brak e cabl e clamps . '
1 0 x 1.2 5 mm60 N- m (6. 0 kg-m ,43 Ib-ft )
12 x 1.2 5 mm95 N- m (9. 5 kg-m ,69 Ib-ft )
34. Remov e th e fron t engin e mount , the n remov e th e
fron t beam .
12 x 1.2 5 mm77 N- m (7. 7 kg-m , 5 6 Ib-ft )
Replace .
12 x 1.2 5 mm -95 N- m (9. 5 kg-m ,69 Ib-ft )
CORROSIO N RESISTAN T BOLT/NU T
35. Remov e th e A/ C compresso r (se e sectio n 22 ), the n
suspen d it fro m th e body .
NOTE :
• D o no t remov e th e compresso r hoses .
• D o no t le t th e compresso r han g b y it s hoses .
36 . Reinstal l th e fron t bea m an d fron t engin e mount .
Han g wit h wir e
or rope .
A/C COMPRESSO R
37. Remov e th e rea r brak e hoses , the n plu g th e brak e
pipe s wit h rubbe r cap s (se e sectio n 19 ).
38 . Disconnec t th e lef t rea r whee l senso r connector ,
then remov e th e whee l senso r wir e clamp s an d sta -
bilize r link .
6 x 1. 0 m m10 N- m (1. 0 kg-m ,7 Ib-ft )
LEFT REA R
WHEE L SENSO R
CONNECTO R
SELF-LOCKIN G NU T
12 x 1.2 5 mm95 N- m (9. 5 kg-m ,69 Ib-ft )Replace .
STABILIZE R
LIN K SELF-LOCKIN
G NU T
12 x 1.2 5 mm85 N- m (8. 5 kg-m , 6 2 Ib-ft )Replace .
REAR BEA M
RO D ASSEMBL Y
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39. Remov e th e righ t whee l senso r wir e clamp s an d
stabilize r link .
6 x 1. 0 m m10 N- m (1. 0 kg-m ,7 Ib-ft )
STABILIZE RLINK
SELF-LOCKIN G NU T
12 x 1.2 5 mm95 N- m (9. 5 kg-m ,69 Ib-ft )Replace .
SELF-LOCKIN G NU T12 x 1.2 5 mm85 N- m (8. 5 kg-m , 6 2 Ib-ft )
Replace .
40. Disconnec t th e fron t secondar y heate d oxyge n senso r
connector , the n remov e th e fron t exhaus t pip e A an d
fron t thre e wa y catalyti c converte r (TWC) .
41 . Separat e th e rea r TW C fro m th e rea r join t pipe .
SELF-LOCKIN G NUT S10 x 1.2 5 mm34 N- m (3. 4 kg-m , 2 5 Ib-ft )Replace .
GASKET SReplace.
GASKETReplace .SELF-LOCKIN G NU T •10 x 1.2 5 mm55 N- m (5. 5 kg-m , 4 0 Ib-ft )Replace .
42. Positio n th e specia l too l unde r th e car . Lowe r th e ca r
jus t abov e th e fixture . Wit h th e hel p o f a n assistant ,
attac h th e fixtur e t o th e subfram e wit h tw o 1 2 m m
nut s an d tw o 1 0 m m bolts .
LOOSEL Y INSTAL L TW O 1 2 m m
NUT S O N STUD S HER E
ENGINE REMOVAL /
INSTALLATIO N
FIXTURE07MAK-PR7020 A
LOOSEL Y INSTAL L ON E
1 0 m m BOL T HER E
43. Adjus t th e pad s o n th e fixtur e t o suppor t th e oi l pa n
an d transmissio n housing .
44 . Lowe r th e ca r s o th e fixtur e i s restin g o n it s caster s
(o r appropriat e platform) .
45 . Remov e th e tw o bolt s fro m th e sid e engin e moun t
nea r th e alternator . Pivo t th e mountin g bracke t int o
th e housin g o f th e body .
BODY SUPPOR TBRACKET
SIDE ENGIN EMOUNT
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Special Tools

Ref.
No.

Tool Number

07HAH—-PJ7010B

07JAA—001020A

07JAB—001020A

07MAA—PR70110

07MAA—PR70120

07MAF—PR9010A

07MAJ—PR7020A

07NAB—001030A

07NAB — 001040A

07742—0010100

07757—-PJ1010A
Description

Valve Guide Reamer, 5.5 mm
Socket, 19 mm Holder Handle
Tappet Adjuster
Tappet Locknut Wrench Valve Spring Compressor Attachment
Extension

VTEC Plug

Holder Attachment, 45 mm
Holder Attachment, 50 mm
Valve Guide Driver, 5.5 mm
Valve Spring Compressor Attachment
Qty

1

1
1
1
1

1
1
1
1
1

1
Page Reference

6-41 ('91-'93) or
('94-'96 Models).

6-12 ('91-'93) or
('94-'96 Models).
6-12 ('91-'93) or
('94-'96 Models).
6-10 ('91-'93) or
('94-'96 Models).
6-10 ('91-'93) or
('94-'96 Models).
6-36('91-'93)or
('94-'96 Models).

6-7,8('91-'93) or
('94-'96 Models).

6-12 ('91-'93) or
('94-'96 Models).

6-12 ('91-'93) or
('94-'96 Models).

6-40 or 41('91-'93) or
('94-'96 Models).
6-36 ('91-'93)or ('94-'96 Models).
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Valve Clearance

Adjustment

NOTE:
Valves should be adjusted cold, when the cylinderhead temperature is less than 100°F (38°C).
Adjustment is the same for both intake and exhaust valves.
Adjust valve clearance at TDC of each cylinder.
Do not rotate the engine counterclockwise. The tim-
ing belt could jump a tooth on the camshaft pulleys.

1. Remove the cylinder head covers.
NOTE: Refer to pages 6-47 ('91-'93),or ('94-'96), 6-48
('91-'93), or ('94-'96) when installing the cylinder head cover.

FRONT:

No.6 No.5 No.4
EXHAUST

INTAKE

No.6 No.5 No.4

REAR:
No.3 No.2 No.1

INTAKE

EXHAUST

No.3 No.2 No.1 (cont'd)

CRANKSHAFT PULLEY
TDC MARK (WHITE PAINT)
POINTER ON

THE LOWER

COVER

REAR:

Number 1 PISTON at TDC

FRONT:

2. Rotate the crankshaft to set No. 1 piston at TDC.
TDC mark (white paint) on the crankshaft pulley
should align with pointer on the timing lower
cover, and TDC grooves on the camshaft pulleysshould align with timing belt cover plates.ProCarManuals.com

Valve Clearance
Adjustment (cont'd)
3. Manually inspect the rocket arms for independentoperation (see page 6-7, 8 ('94-'96), 6-36, 37 ('91-'93).
4. Adjust valves on No.1 cylinder.
• Adjusting screws are on primary and secondary
rocker arms,

Intake: 0.15-0.19 mm (0.006-0.007 in)

Exhaust: 0.17-0.21 mm (0.007-0.008 in)

5. Loosen the locknut, and turn the adjustment screw
until the feeler gauge slides back and forth with a

slight amount of drag.

INTAKE:
TAPPET ADJUSTER

07MAA–PR70110
FEELER

GAUGE

TAPPET LOCKNUT

WRENCH

07MAA–PR70120

EXHAUST: NOTE: Use a mirror to check if the special tool is

positioned on the locknut correctly.

FEELER

GAUGE
6. Tighten the locknut and check the clearance again.
Repeat adjustment if necessary.

INTAKE:
FEELER

GAUGE
LOCKNUT

7 x

0.75
mm

20 N·m
(2.0
kg-m.
14 Ib-ft)

EXHAUST:
FEELER

GAUGE
LOCKNUT

7
x

0.75
mm

20 N·m
(2.0
kg-m,

14 Ib-ft)ProCarManuals.com

7. Rotate the crankshaft 120° clockwise (camshaft pulley

turns 60°). Check that the front intake camshaft pulley

is positioned as shown.

Repeat step 3 to step 6.

Number 4 piston at TDC:

8. Rotate the crankshaft 120° clockwise (camshaft pulley

turns 60°). Check that the front intake camshaft pulley

is positioned as shown.

Repeat step 3 to step 6.

Number 2 piston at TDC:

9. Rotate the crankshaft 120° clockwise (camshaft pulley

turns 60°). Check that the front intake camshaft pulley

is positioned as shown.

Repeat step 3 to step 6.

Number 5 piston at TDC:
10. Rotate the crankshaft 120° clockwise (camshaft pulley

turns 60°). Check that the front intake camshaft pulley

is positioned as shown.

Repeat step 3 to step 6.

Number 3 piston at TDC:

11. Rotate the crankshaft 120° clockwise (camshaft pulley

turns 60°). Check that the front intake camshaft pulley

is positioned as shown.

Repeat step 3 to step 6.

Number 6 piston at TDC:ProCarManuals.com

Timing Belt

Inspection

1. Remove the ignition coil covers and harness clamps.
2. Disconnect the connectors, then remove the ignition
coils.
3. Remove the cylinder head covers,
4. Inspect the timing belt for cracks and coolant or oil soaking.

NOTE:
Replace the belt if coolant or oil soaked.
Remove any oil or solvent that gets on the belt.

Inspect this area

for wear.

Rotate pulley and

Inspect belt.
Tension Adjustment

CAUTION:
Always adjust timing belt tension with the engine cold
Do not rotate the crankshaft when the adjusting bolt
is loose (the timing belt will skid over the teeth of
the rear intake caimshaft pulley).
Adjust the belt tension only when the belt has been
removed and reinstalled or replaced.

NOTE:
Tensioner is spring-loaded to apply proper tension to
the belt automatically after making the following ad-
justment. Inspect the timing belt before adjusting the belt
tension.
Always rotate the crankshaft clockwise. Rotating it
counterclockwise may result in improper adjustment
of the belt tension or cause the belt to jump a tooth
on the camshaft pulleys.
Install the timing beIt with the No. 1 piston at TDC
(see pages 6-18 ('91-'93) or ('94-'96),19 ('91-'93)
or ('94-'96) Remove the slack in the sequence of , and

by turning each camshaft pulley slightly.
Loosen the timing belt adjusting bolt 180° (the slack
at should be eliminated).

Then, tighten the timing belt adjusting bolt.

Verify that No. 1 piston is at TDC (see page 6-19).
Rotate the crankshaft clockwise nine teeth on the
camshaft pulley (The blue mark on the crankshaft pul- ley should line up with the pointer on lower cover).
Loosen
the
timing
belt
adjusting
bolt.

Retighten the adjusting bolt, torque to 43 N·m (4.3
kg-m, 31 Ib-fl).
Direction

of rotation

POINTER ON
LOWER COVER

ADJUSTING BOLT

43N·m (4.3 kg-m,

31 Ib-ft)
BLUE MARK
TDC MARK
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Timing Belt

Installation

Install the timing belt in the reverse order of removal;

Only key points are described here.

NOTE: Clean the middle and lower covers before instal-

lation.

1. Set the timing belt drive pulley so that the No. 1 pis-

ton is at top dead center (TDC). Align the mark on

the teeth side of the timing belt drive pulley to the

pointer on the oil pump.

POINTER

MARK

KEY

TIMING BELT

DRIVE PULLEY

Clean.

2. Set the front camshaft pulleys so that the No. 1 pis-

ton is at TDC. Align the TDC marks on the front

exhaust camshaft pulley and front intake camshaft

pulley to the pointer on the back cover.

Pointer on the

back cover.

FRONT INTAKE

CAMSHAFT PULLEY
FRONT EXHAUST

CAMSHAFT PULLEY

TDC MARKS
3. Set the rear camshaft pulleys so that the No. 1 pis-

ton is at TDC. Align the TDC mark on the rear intake

camshaft pulley to the pointer on the back cover.

Align the rear exhaust camshaft pulley one half

tooth clockwise past TDC.

REAR EXHAUST

CAMSHAFT PULLEY
Pointer on the

back cover.
REAR INTAKE

CAMSHAFT PULLEY

TDC MARKS

4. Install the timing belt tightly in the sequence shown.

Timing belt drive pulley (crankshaft)

Adjusting pulley Front exhaust camshaft pulley

Front intake camshaft pulley Water pump

pulley Rear intake camshaft pulley Rear

exhaust camshaft pulley.

NOTE: Make sure the timing belt drive pulley and

camshaft pulleys are at TDC.

5. Tension the timing belt between the pulleys in the

sequence A to E as shown below.ProCarManuals.com

Cylinder Heads

Removal

Engine removal is not required for this procedure. Make sure jacks and safety stands are
placed properly and hoist brackets ere attached to cor- rect positions on the engine.
CAUTION: Use a fender cover (special tool) to avoid damaging
painted surfaces. Unplug the wiring connectors carefully while holding
the connector portion to avoid damage.
To avoid damaging the cylinder heads, wait until the
engine coolant temperature drops below 100°F
(38°C) before loosening the retaining bolts. Do not open the engine cover when the roof panel is
stored (NSX-T open top).
NOTE:
Unspecified items are common.

Mark all wiring and hoses to avoid misconnection.
Also, be sure that they do not contact other wiring or

hoses or interfere with other parts.

Inspect the timing belt before removing the cylinder

head.

Turn the crankshaft pulley SO that the No. 1 piston is at top dead center (see page 6-19 ('91-'93) or ('94-'96)).
1. Disconnect the negative terminal from the battery.
2. Remove the expansion tank cap. Use care when removing the expan-
sion tank cap to avoid scalding by engine coolant
or steam.
3. Raise the car, then remove the right rear wheel/tire.
4. Drain the engine coolant (see page 10-5 ). 5. Remove the engine under guard, then remove the
front exhaust pipe A.

GASKETS
Replace.

FRONT EXHAUST

PIPE A

SELF-LOCKING NUT

10 x
1.25
mm

55 N·m (5.5 kg-m, 40 Ib-ft)
Replace.
SELF- LOCKING NUT

8 x
1.25
mm

22 N·m (2.2 kg-m. 16 Ib-ft)

Replace.

6. Remove the rear exhaust pipe A.

SELF- LOCKING NUT

8 x
1.25
mm
22 N·m (2.2 kg-m, 16 Ib-ft)

Replace.

REAR

EXHAUST

PIPE A

SELF-LOCKING NUT
10 x
1.25
mm

55 N·m (5.5 kg-m.

40 Ib-ft)

Replace.
GASKETS

Replace.

7. Remove the engine oil cooler base assembly (see
page 6-15 ('91-'93) or ('94-'96).

8. Lower the car.
9. Remove the strut brace (see page 5-3 ).ProCarManuals.com

36. Remov e th e fron t an d rea r bac k covers .
REAR BAC K
COVE R
RUBBER SEAL S
FRON T BAC K
COVE R
37. Loose n th e rocke r ar m locknut s an d th e adjustin g
screws .
38. Remov e th e camshaf t holde r plates , camshaf t holder s
and camshafts .
FRONT INTAK ECAMSHAF T
CAMSHAFT HOLDE R
PLATE S
RUBBE R SEA L
FRON T EXHAUS TCAMSHAF T
OIL SEAL S
Replace .
39. Remov e th e cylinde r hea d bolts , the n remov e th e
cylinde r head .
CAUTION : T o preven t warpage , unscre w th e bolt s
i n sequenc e 1/ 3 tur n a t a time ; repea t th e sequenc e
unti l al l bolt s ar e loosened .
CYLINDE R HEA D BOLT S LOOSENIN G SEQUENC E
NOTE : Separat e th e cylinde r hea d fro m th e bloc k
with a fla t blad e screwdrive r a s shown .
40. Remov e th e fron t an d rea r exhaus t manifold s (se e
page 9-4 ).
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